1. Field of the Invention
The present invention relates to a liquid jet recording head for jetting liquid from an orifice and forming droplets and a method of manufacturing the same.
2. Related Background Art
Conventionally, there is known a liquid jet recording method (ink jet recording method) for jetting liquid from an orifice and executing recording by a droplet thereof. For example, Japanese Laid-Open Patent Application No. 54-51837 discloses a type of a liquid jet recording method by which power for jetting droplets is obtained by applying thermal energy to liquid. This kind of the recording method is characterized in that liquid to which the action of thermal energy is applied is heated to produce bubbles, droplets are formed from the orifice at the extreme end of a recording head by an acting force due to the production of the bubbles, and the droplets are deposited on a recording member for recording information.
The liquid jet portion of a recording head applied to this recording method includes an orifice for jetting liquid and a liquid flow path communicating with the orifice. A portion of the liquid flow path is composed as a heat acting portion where thermal energy for jetting droplets is acted to the liquid. Further, the recording head includes a heat generating resistance layer as a thermal converter serving as a thermal energy generating means and an upper protection layer for protecting the heat generating resistance layer from ink.
In order to effectively bubble ink in this type of the recording method, a bubbling surface must be heated to about 300xc2x0 C. at very short pulse intervals and the temperature thereof must be returned to a room temperature in an order of microsecond. For this purpose, the heat generating resistance layer itself must have a reduced thermal capacity. Further, a thermal resistance between the heat generating resistance layer and the bubbling surface (more specifically, the thermal resistance of electrodes and the upper protection layer) must be also reduced because of the same reason. On the other hand, since the heat generating resistance layer, electrodes and upper protection layer are usually formed by lamination, if the heat generating resistance layer and electrodes have an excessively thin width, the step of these portions is relatively increased. When the stepped portion is increased, the quality of the film of the upper protection layer covering these portions is deteriorated and thus a problem of the electric erosion and the like of the electrodes and heat generating resistance layer arises.
Therefore, it is preferable to make a film thickness thin as a means for reducing the thermal capacity of the heat generating resistance layer. Further, a thermal resistance can be reduced by making the film thickness of the electrodes and upper protection layer. A specific film thickness is preferably 0.1 to 1 micron. Conventionally, when an inorganic material used for the heat generating resistance layer, electrodes and protection layer is formed to such a film thickness, the film is formed by using a vacuum process such as a vacuum vapor deposition and sputtering method. The vacuum process, however, needs a large manufacturing apparatus as well as the productivity thereof is not so good because severe environmental conditions are required for the formation of a good thin film. Further, this process is not always preferable from the view point of cost because the manufacturing apparatus is expensive.
Taking the above problem into consideration, the inventor has discovered a completely novel method as a result of a zealous study. The present invention provides a method of manufacturing a liquid jet recording head by which a thin film composed of an inorganic material can be formed by a conventionally use a method such as a printing method and coating method executed in the atmosphere, the method being able to be relatively easily achieved, a head made by the manufacturing method, and a liquid jet recording apparatus including the head and a member for mounting the head. A main object of the present invention is to provide a liquid jet recording apparatus including a heat acting portion communicating with a liquid jetting orifice for applying thermal energy to a liquid to form a bubble, an electrothermal converter for generating the thermal energy, a heat generating resistance layer contained in the electrothermal converter, and electrode layers for imposing a voltage to the heat generating resistance layer contained in the electrothermal converter, wherein the heat generating resistance layer is composed mainly of an organic resinate.
The organic resinate used in the present invention generally includes carboxylate, carboxylic acid ester, arkoxide, rosin ester, polycyclic organic compound, siloxanes, bolic acid compound, and the like.
According to the present invention, since a desired thin film can be easily formed in the atmosphere, a highly reliable liquid jet recording head of low cost with high productivity can be provided. Further, the liquid jet recording head can stably jet liquid even if it is driven at a high frequency because a thick film such as that formed of a dispersed material of inorganic material and glass used in a conventional printing method and coating method is not formed and the surface property of a film is not degraded.
Further, the inventors have discovered that the present invention has an advantage completely different from the aforesaid advantage in addition to it. That is, according to the present invention, defective portions such as pin holes and the like of a thin film conventionally found in a sputtering method and the like are greatly reduced. This is supposed to be caused by the fact that the thin film is not liable to be porous because it is not affected by a high voltage imposed thereon and severe environmental conditions. This advantage can further reduce the electric erosion of a heat generating resistance layer and electrode by ink.
As described above, the present invention is epoch-making in that when a thin film is formed of an inorganic material, the film is made as fine as a film composed of an organic material and the film can be formed easily.